1. Technical Field
The invention relates to meat cutting devices and particularly to a power driven meat cutting knife adapted to be manually held and manipulated for the quick and easy removal of meat from carcasses and bones. More particularly, the invention relates to an improved knife and the drive system therefore in which the handle of the knife extends vertically therefrom and parallel with the rotational axis of a ring-shaped cutting blade; in which the knife is suspended vertically above a work table and is easily moved by the operator into trimming position; and in which vertical movement of the knife with respect to the work table automatically controls the actuation and deactuation of the power supply to the trimming blade.
2. Background Information
Various styles of power driven meat cutting tools have been devised and various drive system therefor, wherein a ring blade is rotatably mounted on a blade holder which is mounted on a manually operated, power driven handpiece. These tools have been used for some time to facilitate the removal of meat from a carcass, primarily in the trimming operation or for removing the meat remains from the bones. These meat cutting tools are either electrically or pneumatically driven. Some examples of the electric prior meat cutting tools are shown in U.S. Pat. Nos. 3,269,010, 3,461,557, 3,852,882, 4,324,043 and 4,575,938. Examples of pneumatic driven tools are shown in U.S. Pat. Nos. 3,852,882 and 4,575,938. Drive systems for these electric and pneumatic driven tools also are shown in these patents.
These power driven tools or trimming knives, as they are generally referred to in the industry, consist of a tubular handle which is connected to an arcuate shaped blade attachment front portion. The handle is formed with a hollow bore extending throughout the longitudinal length of the handle. The blade is rotatably mounted on an annular blade holder which is mounted on the front end of the blade attachment portion. The power supply for rotating the blade is usually a flexible drive cable which is connected to a remotely mounted electric motor or a fluid supply line which is connected to a remote source of pressurized air which is connected to an air motor mounted within the handle. Both the flexible drive cable or the output shaft of the air motor are connected to a pinion gear or the like rotatably mounted within the handle or blade holder attachment member. This gear is provided with a series of teeth for rotatably engaging teeth on one end of the cutting blade for rotating the blade in a circular motion.
However, in all of these prior art knives, the handle extends outwardly in the same general direction as the plane of the cutting blade, or perpendicular to the rotational axis of the circular cutting blade, which axis extends perpendicular to the plane of the blade and passes through the center thereof. This arrangement and the drive system therefor requires the operator to completely support the weight of the knife while it is being utilized in a trimming operation. It also requires constant twisting and flexing of the connected drive cable or pneumatic supply line during the cutting procedure. Although the trimming knife and connected power supply line is relatively lightweight, it does over a period of time, such as throughout a operators workshift, cause operator hand and arm fatigue reducing production output and possible discomfort to the operator. Operators have found that for certain trimming operations such as when the blade moves horizontally across the workpiece, it is desirable to have the handle extending vertically from the workpiece. However, this requires the makeshift attachment of a separate handle to the handpiece while still requiring the power supply line to extend outwardly from the handpiece perpendicular to the rotational axis of the cutting blade. It also increases the weight of the trimming knife adding to the further discomfort and fatigue of the operator.
It is desirable in the drive system for such trimming knives to provide ON/OFF switches whereby the operator can deenergize the machine during short stoppages in the trimming procedures to enable him to set the knife down and flex his hand to relive the fatigue and stress thereon. However, nearly all known prior art control systems require the operator to physically put the knife on the work table after deenergizing the same by a switch on the knife or a switch located above at the electric drive motor location. This procedure requires additional time and motion which may not be practical during trimming procedures wherein the meat is brought to the operator on a moving table or conveyor, and the operator does not have sufficient time during the passage of each carcass to relax his or her grip on the knife.
Therefore, a need exists for a trimming knife in which the handle extends vertically from the knife and in which the power supply line enters the knife through the handle as in prior trimming knives, without affecting the remaining components of the knife; and in particular for a knife in which part of the knife's weight can be supported externally of the operator to reduce operator fatigue; and in which an improved safety control ON/OFF switching mechanism is provided to enable the operator to occasionally relax his or her grip on the trimming knife without the machine remaining energized.